At present, electrical energy is a significant resource, so it is increasing day by day. When electrical demand increases, then the distribution system should have sufficient capacity to meet that demand. So this capacity is measured by engineers with the demand factor (Df) formula. It is a very significant factor for engineers, homes, businesses, etc. Generally, it is measured every month but most companies choose to measure it periodically at shorter intervals to check the maximum load in real time. This article discusses an overview of a demand factor – working with applications.
What is the Demand Factor?
The demand factor is a security parameter within the electrical distribution system that signifies the quantity of power necessary for a system to work at its peak load. This is very helpful in determining a capacity of a power system & the required reserve capacity to meet peak loads. The formula of (Df) is a process to analyze the highest demand on a system. So it determines how much capacity a system should have to meet the demands of users. This formula is based on the peak load principle & it is used to compute the highest amount of power a system can utilize at any specified time. The demand factor formula is given below.
Demand Factor Formula
Affecting Factors
There are many factors that influence the demand factor are amount of power and the load factor which are discussed below.
- The most significant factor that the system is necessary to provide is the amount of power. So, this is determined by the type & number of electrical devices linked to the system.
- The second important factor is the load factor because it determines actually how much power is being utilized by the connected devices to the system.
- Other factors that affect demand are the efficiency of the connected devices to the system as well as the daytime or year once power is being utilized.
- For instance, generally in the summer season, the (Df) is higher as compared to the winter season.
Demand Factor in Load Calculation
The demand factor in load can be calculated by using the following steps.
- First, you need to decide on the electrical loads that are available on the system.
- When you determined all the electrical loads, then you can determine the highest demand by adding up all of the numbers.
- After that, determine the total connected electrical loads to your system.
- Lastly, you can measure the demand factor by simply dividing the highest demand by the entirety connected electrical load to the system.
Example
There are four 20W bulbs connected to your electrical system of the home. But, you are simply using at a time three bulbs. So from this, you can decide the highest demand by simply adding the requirements of energy for the bulbs that can be functioned together.
3 bulbs x 20W (each) = 60W.
But, since you have four bulbs, then the load connected is equivalent to:
4 bulbs x 20W (each) = 80W.
Thus, the Demand Factor would be (0.6) by applying the formula of demand factor. If you want to calculate the Df in terms of (%) percentage, then you can multiply the outcome by 120W.
So, 0.6 x 80 = 54%
Demand Factor Table
The typical demand factor values for electric load and utility are listed below.
Electric Load & Utility | Demand Factor |
1 Motor | 1 |
Up to 10 Motors | 0.75 |
Up to 20 Motors | 0.65 |
Up to 30 Motors | 0.6 |
Hospital | 0.5 |
| School/Office | 0.4 |
| Factory/Restaurant | 0.7 |
| Shops/Airport/bank | 0.6 |
| Factory/Workshop | 0.8 |
Difference between Load Factor Vs Demand Factor Vs Diversity Factor
The difference between load factor, demand factor, and diversity factor is discussed below.
Load Factor | Demand Factor | Diversity Factor |
| Load factor can be defined as; it is the ratio of the average load & the maximum demand for a specified time period. | The demand factor can be defined as; it is the ratio of the maximum demand on an electric power station to the load connected to it. | The diversity factor can be defined as; it is the ratio of the sum of individual max demands on the power station to the max demand on the power station. |
| The load factor formula can be written mathematically as; Load Factor = Average Load/Maximum Demand | The (Df)formula can be written mathematically as; Demand Factor = Maximum Demand /Connected Load. | Diversity Factor = Sum of individual max demands/Max demand on the power station. |
| The power station’s load factor is less than 1 always. | The power station’s demand factor is less than 1 always. | The power station’s diversity factor of is greater than 1 always. |
| The load factor is used to measure the efficiency of electrical energy usage in your home. | The Df is used to measure the amount of total demand for a system that is being produced by different portions. | The diversity factor is mainly used to estimate a particular node’s load within the system. |
Advantages
The demand factor advantages include the following.
- Generally, the demand factor value is below 1 because usually, the highest demand on the power station is below the load connected to the power station. The information on this factor is significant in deciding the equipment capacity for the power plant.
- This factor provides an overall layout of the quantity of power used by a house. When the Df is high then the power consumption would be high.
- The demand factor permits a feeder ampearcity to be below 100 of all the branch-circuit loads associated with it.
Applications
The demand factor applications include the following.
- The demand factor is used to measure the sub-main size which is feeding a fixed load or Subpanel like an electric motor etc.
- In the electronics, electrical power & telecommunication industries, this factor is mainly utilized to refer to the partial amount of some quantity being utilized relative to the highest amount that could be utilized by the same system. The demand factor is equal to or less than one always.
- The Df is useful in determining the highest amount of energy demand that a system part is capable of handling.
- A demand factor in the electrical industry is used to determine the amount of total demand for a system that is being produced by different portions.
Power managers & Engineers can utilize this factor on a power grid system to redirect electrical loads.
Why Do We Need a Demand Factor?
Usually, the maximum demand on the power station is below the connected load to the power station. So the Df is significant to determine the equipment capacity for the power plant.
What Causes Peak Demand?
Peak demand can exceed the highest supply levels that the electrical power industry can produce, resulting in load shedding & power outages.
What is the Maximum Demand Meter?
The maximum Demand meter is mainly used to monitor thermal loading within Networks, Power Distribution systems, Machines etc. So it indicates the highest loading current over a stage.
What is Demand Factor in Power System?
The demand factor in a power system refers to the highest amount of electrical power that is being utilized at a specified time.
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Thus, this is an overview of the demand factor – advantages and applications. Generally, the demand factor measures the capacity of a system used. So, it is significant to know that this factor determines whether the system is overloaded or not. Once this factor is close to 1, then the system is overloaded & extra capacity needs to be included. Here is a question for you, what is the load factor?